Staged fuel injection with in-line pumps: simulation and experiments

It is well known that the combustion development in Diesel engines is strongly dependent on the injected fuel rate versus crank angle. In the last few years new technologies for controlling the injection rate have been developed and tested; many researchers have investigated the effect of split injection on both particulate and NO_x emissions. For small diesel engines electronically controlled injection systems have too high incidence on the final costs.

In this paper a mechanical injection system is presented that takes advantage of a modified in-line pump order to achieve a two-stage injection. Tests have been carried out by means of an atmospheric test rig the fuel injection system. The experimental results confirm that the two-stage injection occurs when utilizing the modified pump. A computer code, developed by the authors, has been used in order to simulate the modified injection system; the model worked out to be very useful to determine the geometrical features the pump.